Simplify the following expression: ${4z+9+9z-3}$
Rewrite the expression to group the ${z}$ terms and numeric terms: $ {4z + 9z} + {9 - 3}$ Combine the ${z}$ terms: $ {13z} + {9 - 3}$ Combine the numeric terms: $ {13z} + {6}$ The simplified expression is $13z+6$